Part 6: Cloud Security: Shared Responsibility and Real Accountability

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Introduction

The cloud is no longer just an option; for many organizations, it’s now the default. Whether using Software-as-a-Service (SaaS), building on Infrastructure-as-a-Service (IaaS), or deploying entire platforms with Kubernetes and containers, the cloud provides unmatched flexibility, scalability, and speed.

But with that freedom comes complexity. Unlike traditional infrastructure, cloud environments are ephemeral, decentralized, and abstracted, making them powerful but also difficult to secure. Assets appear and vanish within seconds. Workloads span multiple regions. Teams deploy services with just a few lines of code.

In this new world, security must be redefined. This part of the series explores what cloud security means, how responsibilities are divided (and sometimes misunderstood), and what it takes to protect workloads, data, and identities in a platform you don’t fully control.

Understanding the Shared Responsibility Model

At the core of cloud security is the Shared Responsibility Model, a framework that defines the responsibilities of each party in a cloud environment. While the details may differ slightly between providers, the fundamental idea is the same.

• Cloud provider: Secures the cloud infrastructure, data centers, physical hosts, networking, and foundational services.
• Cloud customer: Secures everything they deploy in the cloud, including configurations, access, data, workloads, and user activity.

This model applies differently across service types:

• SaaS (e.g., Microsoft 365, Salesforce): The provider handles almost everything, but the customer is still responsible for access control, user behavior, and data governance.
• PaaS (e.g., AWS Lambda, Azure App Services): Customers manage applications and data, while the provider secures runtime, OS, and infrastructure.
• IaaS (e.g., EC2, Google Cloud Compute Engine): The provider maintains hardware and virtualization; customers must secure OS, apps, and everything built on top.

Misunderstanding this model is one of the most common causes of cloud security breaches, especially when people assume the provider has handled configuration and access control, but they haven’t.

The Most Common Cloud Security Challenges

While the cloud transforms many aspects, the core principles of security stay the same: confidentiality, integrity, and availability. However, in the cloud, these objectives must be met within flexible, automated environments that are often shared with others.

Common cloud security challenges include:

• Misconfigurations: Open storage buckets, exposed APIs, and overly permissive IAM roles are frequent culprits in cloud breaches.
• Lack of visibility: Traditional security tools often struggle to monitor ephemeral workloads or managed services.
• Shadow IT and sprawl: Teams may launch cloud resources outside IT’s purview, increasing risk without governance.
• Complex identity management: Federated identities, service accounts, and machine-to-machine authentication introduce new attack surfaces.
• Multi-cloud inconsistencies: Security controls differ between AWS, Azure, and Google Cloud, making unified governance difficult.

Organizations require cloud-native security capabilities that align with modern development and deployment practices to address these issues.

Key Pillars of Modern Cloud Security

Securing cloud environments requires going beyond firewalls and endpoint agents. Instead, cloud security must be:

1. Identity-Centric

Identity has become the new perimeter in the cloud. Users, services, and functions must be thoroughly authenticated, authorized, and monitored.

• Use role-based access control (RBAC) and least-privilege principles
• Enforce MFA for all users, including admins
• Audit service accounts and rotate credentials regularly

2. Configuration-Driven

Infrastructure is increasingly managed as code, so security must be integrated into the deployment process and not added later.

• Use Infrastructure as Code (IaC) scanning to catch risks pre-deployment
• Apply policy as code to enforce compliance and guardrails
• Automate security checks in CI/CD pipelines

3. Continuously Monitored

Cloud environments constantly evolve. Without real-time monitoring, blind spots happen quickly.

• Deploy Cloud Security Posture Management (CSPM) tools to monitor for misconfigurations
• Use Cloud Workload Protection Platforms (CWPP) for runtime analysis of VMs, containers, and functions
• Centralize logs and events in a SIEM for threat detection and compliance

4. Data-Aware

Cloud security must protect both the infrastructure and the data that flows through it.

• Classify and encrypt sensitive data at rest and in transit
• Apply data loss prevention (DLP) policies where appropriate
• Control where data is stored (geolocation, residency, cross-border policies)

Securing SaaS, PaaS, and IaaS: Not a One-Size-Fits-All Approach

Each cloud model has its priorities. In SaaS, the focus is often on identity, data security, and monitoring user behavior. In PaaS, it’s about securing application logic, managing secrets, and protecting APIs. In IaaS, the entire stack is involved, from OS hardening to network access control and patching.

To secure these environments effectively:

• Align your security architecture with the cloud consumption model
• Standardize tools and policies across providers to reduce fragmentation
• Build a Cloud Center of Excellence (CCoE) or equivalent governance body to define policies, patterns, and shared services

Compliance, Governance, and Cloud-Native Controls

Many industries have strict regulations regarding data storage, access, and auditing. The cloud doesn’t eliminate these obligations; it makes them more complicated, especially in multi-cloud and hybrid environments.

Fortunately, cloud providers supply built-in tools to assist with compliance and governance.

• AWS Config, Azure Policy, Google Cloud Organization Policies for configuration tracking
• Key management services (KMS) and HSM-backed encryption
• Audit trails (e.g., AWS CloudTrail, Azure Monitor, Google Cloud Audit Logs)

However, these tools must be activated, configured, and monitored; they don’t secure your workloads by default.

A robust governance framework is crucial: clear ownership of cloud accounts, consistent tagging and resource naming, and regular policy reviews.

Conclusion: Taking Responsibility for Your Share of the Cloud

The cloud provides speed, scale, and opportunity, but security is never “outsourced.” The Shared Responsibility Model offers flexibility, but it also requires real accountability. Mistakes in the cloud often occur quickly and are frequently made public.

Organizations must embed security into their cloud journey from day one to stay secure, aligning teams, tools, and processes with the realities of dynamic, API-driven infrastructure. That means cloud security should not be treated as a checklist but as a continuous discipline integrated with DevOps, compliance, and business strategy.

In Part 7, we’ll connect the dots between all four domains, endpoint, network, datacenter, and cloud, and explore how organizations can design a unified infrastructure security strategy, including the role of service providers, platforms, and governance frameworks.